Compressor or pump



Feb. 14, H. W. BELL COMPRESSOR OR PUMP Filed Oct. 20, 1945 I 5 Shee'ts-Sheet l f'iqJ INVENTOR. Harvey W Bel/ A T TORNEYS Feb. 14, 1950 H. w. BELL COMPRESSOR 0R- PUMP Filed Oct. 20, 1945 5 Sheets-Sheet 2 INVEN TOR. Harvey WBeI/ AT TORNEYS Feb. 14, 1950 H. w. BELL 24 71 75 COMPRESSOR OR PUMP Filed Oct. 20, 1945 s Sheets-Sheet 3 INVENTOR. Ha'rvey W Bell ATTORNEY Feb. 14, 1950 H, w, BELL 2,497,575

COMPRESSOR 0R PUMP 5 Sheets-Sheet 4 Filed Oct. 20, 1945 INVENTOR. Harvey Wfiel/ wwww Feb. 14, 1950 H. w. BELL COMPRESSOR OR PUMP Filed Oct. 20, 1945 5 Sheets-Sheet 5 INVEN TOR. Han e y W Be/l ATTORN Patented Feb. 14, 1950 UNITED STATES PATENT OFFICE 2,497,515 COMPRESSOR R PUMP Harvey W. Bell, Yonkers, N. Y. Application October 20, 1945, Serial No. 623,584

This invention relates to compressors or pumps, and more particularly to a mechanism for varying their effective volumetric displacement or capacity.

It is in the nature of an improvement on the control mechanism described in my pending application Serial No. 559,361, filed October 19, 1944, now Patent Number 2,453,402, granted November 9, 1948.

In accordance with the invention described in said co-pending application, the cylinder of the compressor, whether it isof the single stage or multi-stage type, has an unloading valve which is positively maintained by a mechanical device in open position from the beginning of the compression stroke to a selected phase of said stroke prior to the opening of the discharge or delivery valve. This unloading valve may be the only inlet suction valve of the cylinder, or may be provided in addition to the ordinary inlet valve. While this unloading valve isopen, air cannot be compressed in the cylinder and compression cannot begin until this valve is closed. This valve is initially opened during the final stages of the suction stroke, and is maintained'open during the initial stages of the compression stroke, according to the setting of the valve control means. Means are provided for adjusting the phasing of the opening and closing of the un-' loading valve with respect to the stroke cycle of the piston. This adjustment is desirably so ef-' fected that the point in the suction stroke-whenthe valve opens (as measured from the end of the suction stroke) corresponds to" the phase in the compression stroke when said valve closes (as measured from the beginning of the compression stroke). For example, when the compressor is running with its displacement 100% effective,-

there is no mechanical opening or closing of the unloading valve; at 50% displacement, it would be opened approximately at midsection of the suction stroke if suction has not previously opened it and closed at midsection of the compression stroke; at one-third capacity, the unloading valve is opened during the suction stroke after the piston has traveled approximately one-' third of said stroke, and is closed after traveling two-thirds of its compression stroke; and'at zero displacement, it is open throughout the whole of The unloading valve is so operated that, with any adjustment of its control, it remains closed during the suction stroke untilthe pressure of the suction and compression strokes.

than" the pressure the air in the cylinder is less Therefore, at the of the air in the inlet pipe.

Claims; (01. 230-25) 2 end of the compression stroke, any compressed air in the clearance space will be reexpanded against the piston, and will not be released through the unloading valve. A substantial amount of the work of compressing this air in the clearance space is thereby returned to the piston and will not be lost.

With the control mechanism described in this said co-pending application, the unloading valve is operated by a rotating cam driven by the main crankshaft. This cam is of such contour that it is relatively difficult to fashion and relatively expensive. g

It is an object of the present invention to provide a valve control mechanism which is simpler and less expensive than the one shown in the said co-pending application.

The action of the unloading valve in the present form of embodiment of compressor is exactly the same. But an oscillating instead of rotating cam is employed to operate the valve. The valve control cam of the present invention normally oscillates through an angle of approximately 30, but the portion of its circumference in contact with the valve actuating roller may be shifted. This is accomplished by means of a.

control lever which serves to move the fulcrum of the mechanism for oscillating the cam. In one extreme position of the control lever the valve is held open continuously, while in another it is not held open at all, and in between it is" held open during varying first portions of the compression strokes of the piston.

For other objects and for a better understanding of the invention, reference may be had to the following detailed description taken in connec-' tion with the accompanying drawing, in which Fig. 1 is an end elevational view of the compressor having the special unloading valve and with the valve gear operating mechanism of the present invention directed to operate this valve;,

ing the various valve arrangements associated with the compressor;

Figs. 5 and 6 are also diagrammatic illustrations of the valve gear mechanism where the oscillating cam has been moved to a position toeffect automatically the opening and closing of the special valve, the oscillating cam being shown respectively at different ends of its stroke; and

Figs. '7 and 8 are respectively diagrammatic illustrations of the valve gear mechanism showing the relative position of the parts where the cam has been moved to a position where the compressor operates at its maximum capacity and where the cam has been adjusted to a position where the valve is left open continuously and the compressor reduced to zero capacity.

Referring now to Figs. 1 to 4 there .is shown a compressor l5 having an air-cooled cylinder [6 connected at its base by means of bolts H to :a crankcase I 8. Extending through the ends of the crankcase is a crank shaft 2| having a fiy-wheel Zia, and adapted to operate a connecting rod .22 and a piston 23 within the cylinder 56. upper end of the cylinder is is closed by 'a water The position within an opening 54 in the cylinder Hi. The valve stem 5! when the valve ll is closed, extends forwardly for some distance beyond the flange 53. It is urged to this position by a valve spring 54' operating between a Washer 55 fixed on the end of the valve stem and the rear portion 56 of the valve cage 52. .The front end of the valve stem 5! lies in a chamber 5'2 formed within a housing plate 53 connected to the cylinder t8 by means of bolts 59. The housing flanges 58' he against the valve cage flange '53 and the bolts which retain this housing also retain the valve cage. Extending upwardly into the chamberfil andadapted to engage the end of the valve stem to operate the valve is a tappet 65. This tappetdsasecured to a transversely extending shaft 62, and extends upwardly through the housing 58. The shaft '62 is supported by a laterally excooled cover 24, which may be like thatshown in I my application No. 559,361 having a portion 25 extending downinto the cylinder chamber. Inlet and outlet water pipes 26 and 2'! connect with the water cooled head 24 to supply water thereto and to discharge the heated cooling waters Referring particularly to Fig. 4 there are provided on the cylinder l6 inlet and outlet ports 28 and 29. Contained within the inlet .port 28 is an automatic suction valve mechanism 3! through which the fluid being supplied to the cylinder is controlled. As the piston makes a suction stroke the valve element 33 of this mechanism is'o-pened away from the passages 3d against the action of springs 35, only one of which is shown. The inlet .port 28 receives the gas to be compressed from an intake pipe 36 bolted to the cylinder 16 by means of bolts 31'. By the same bolt means 31, the valve mechanism 3i is supported within the inlet .and in axial alignment with an extension 38 of the inlet port. The air entering the port 28 can pass about the cylinder I6 through a passageway 39 which a control valve 4| .for unloading the compressor is disposed The valve 4! is operable to and from a-seat portion42 to permit the entrance and exit of the fluid to and from the :passage 39. The function of this valve is described in my co-pending application, but will'be further described herein when detailed description 'is being made of the mechanism for operating this valve.

At a .90 angle from the inlet valve mechanism "3i and diametrically opposed to the special valve 41 is the outlet port '29 in which is disposed an automatic exhaust valve mechanism d3, which includes a valve .p'late Mcooperating with exhaust passages '45 and so retained as to close olf' the same by means of springs 4'5, only one of which is shown. The valve mechanism 43 is supported "by the same bolts 'flwhich connect the outlet pipe 48 to the cylinder H; at the outlet port 29.

While the compressor is working at maximum capacity the "operation of the inlet and outlet valve mechanisms is entirely automatic and well understood in the art. The valve'mechanism 3| is opened during the-suction stroke of the piston 23 to suck in air or other fluid :from the inlet [pipe :36 and closed during the compression or upstroke of the piston 23, to exhaust the compressed air or other gas through the :outlet valve mechanism 43. Both of these valve mechanisms are of the one way type.

The special .valve 4! has a valve stem 5.! which is retained in a valve supporting cage 52. This cage 52 hasradially extending flanges 53 by which the cage connected and retained in its proper tending sleeve formation 63 thereof to a point where a roller 64 on an arm 65 engages an oscillating .cam 66, located .at one side .of the compressor. A stuffing box including .a gland 61 surrounds .the shaft at the end of the sleeve formation '63 to retain a packing, not shown, within the sleeve 63.

The arm 65 has a bifurcated portion 68 connecting with the-shaft 62. The arm may .rotate on the shaft but is limited against leftward rotation by an adjustable take up .screw .H on an arm 12 f xed between the bifurcations of the portion 68 by a pin 1-3. By adjusting the screw H the position of the .roller 64 relativeto cam 56 is adjusted.

The cam 66 is pivoted on a stud '16 :of an vupstanding bracket Jl fixed to the bottom of the cylinder 143 by means of screws 18. The .camiifi is rocked on the ;pivot 16 by an eccentric 79 secured to one end of the crankshaft 2i by a key 8]. surrounding this eccentric is a device including two transversely-extending members 82 each having a circular opening .83 adapted to contain the eccentric J9. The members 82 carry asstud or fulcrum point 34 to which a link 85 is connected. This link-85 at its vupperend connects with an .arm 86 as indicatedat 81 to rock the cam 66. In order to.alter the position of the cam 56 so as toplace the .roller 64 either ona low portion .-9l or on a high portion -92 of the cam .66 or in an intermediate position where the roller will .be worked by sections of both the low and raised portions of the cam, there is provided a hand-adiusting mechanism .93 which includes a hand .lever 94 pivoted on .a portion 95 of the eccentric IQ, .the portion 95 being concentric with the crank shaft 2!. The lever 941s connected through links -96 with the forward ends of members 82 by a pin .95. Ill-order to retain the lever 94 in its adjusted position there is provided thereon a :bolt 91 adapted to be slid through an arcuateslot .98 111.2. bracket 99 fixed .to the gear case l8 by screws Ill. The belt 91 has .a nut L92 .for looking a hand .lever 95 to the bracket Q9 and in .its adjusted position.

In the form of construction which is nowvpreferred, the .angle through which the eccentric 19 causes the-cam 66 to oscillate is.30.. Adjustment ofthelever 94 can'causethe cam to move through an angle of 42".. Different portions of the circumference of the cam may thus be caused to contact the valve actuating .roller .64 While the eccentric is oscillating the cam.

Inll'ig. .7 the control-or hand lever 94 lisshown ashaving been pulled to .theileft as .far as it will go. .Asa result the members-82 are so positioned on the eccentric 19 that only the upper cam face portion 9| ofthe cam engages roller 64 ,as-.,the cam oscillates. The cam, therefore, does not lift the roller at any time during its oscillation, and the valve 4| is at no time held open mechanically sothat the compressor operates at maximum capacity. If, now, the lever is moved to the right, as for example to the intermediate position shown inFigs. 5 and 6, the cam 9| will lift the roller 64 in the middle of the suction stroke and thus open valve 4| (if the same has not already been opened by the suction in the cylinder) and hold valve 4| open during the remainder of the suction stroke and during the first half of the compression stroke, by reason of the fact that during the oscillation of the cam the raised and lowered p01.- tions of the cam engage the roller successively; The compressor, therefore, operates at only partial capacity. It will thus be apparent that the further the lever 94 is moved to the right, the greater will be the portion of the compression stroke during which the valve is held open.

When the lever 94 is all the way to the right as in Fig. 8 the cam will oscillate without permitting the roller to run off the dwell or raised portion 92, so that the valve 4| is held open continuously and the capacity of the compressor is reduced to zero.

It will be noted that the construction of the control mechanism is such that the shaft of the compressor may be rotated in either direction with equal results for any position of the control lever. If desired, the valve gear may be enclosed and run in an oil bath, or it may be enclosed in a dustproof casing. It will also be noted that the form of construction of the valve mechanism is such that it lends itself to multi-cylinder compressors, and that it may readily be balanced.

As previously noted, as far as certain aspects of the present invention are concerned, valve 3| may be omitted because valve 4| can be opened by suction and serve the same purpose, therefore, as present valve 3|. In other words, valve 4| in such modified form of construction would serve a double purpose, that is, as an automatic suction valve and also as a mechanical unloading valve.

I have described what I believe to be the best form of my invention. I do not wish, however, to be confined to the embodiment shown, but what I desire to cover by Letters Patent is set forth in the appended claims.

I claim:

1. In a compressor, a cylinder, a crankcase for supporting the cylinder, a crankshaft in the crankcase and extending through one end thereof, a piston operated by the crankshaft within the cylinder, said cylinder having the usual automatic intake and outlet valve mechanisms, an unloading valve in the cylinder and operable to prevent compression in said cylinder while the valve is open, an eccentric on the projected end of the crankshaft, a transversely-extending member on the eccentric means responsive to the rotation of said eccentric for oscillating said tranverse member, linkage means extending between the transverse member and the unloading valve for effecting the operation of said unloading valve, and hand-adjusting means connected with the transverse member to adjust the same on the eccentric whereby to vary the phase relationship between the operation of the unloading valve and the stroke cycle of the piston.

2. In a compressor, a cylinder, a piston reciprocable in the cylinder, a crankcase on which the cylinder is mounted, a crankshaft within the crankcase and projecting laterally from one end thereof, automatic inlet and outlet valve mechanlsms, an unloading valve for the compression chamber, means for operating the unloading valve comprising an eccentric on the crankshaft, a transversely-extending member on the eccentric to be operated by the same, an oscillating type cam pivoted on the compressor and having lower and raised cam face portions, and a link connected betweenthe transverse member and the oscillating cam to transmit the oscillating movement of the transverse member to the cam, roller means operable upon the cam surface for imparting ;movement from the cam to the unloading valve, and means for adjusting the phase relationship between the cam and the stroke cycle of the piston, including a hand lever connected with the transverse member on the eccentric and adapted to alter the oscillatory cam so that the roller means may be affected by either the lower portion or the raised portion of the cam face or by both. v V

3. A compressor comprising a cylinder having inlet and outlet valves, a shaft, a piston reciprocable in the cylinder by rotation of said shaft, an unloading valve at the closed end of said cylinder adapted to prevent compression in the cylinder while the same is open, means for operating said unloading valve comprising acam, a member supported on said shaft, means responsive to the rotation of said shaft for oscillating said member about said shaft, and a connection between said member and said cam for oscillating said cam, and means for adjusting the angular position of said member with respect to the stroke phase of said piston to vary the phase relationship between said cam and the stroke cycle.

4. A compressor as described in claim 3, in which said means for oscillating said member about said shaft includes an eccentric aflixed to said shaft and embraced by said member with a rotative fit, and a pivot support for said member spaced from said shaft.

5. A compressor as described in claim 3, in which said means for oscillating said member about said shaft includes a pivot support for said member spaced from said shaft, and said adjusting means operates to adjust the position of said pivot support.

6. A compressor as described in claim 3, in which said means for oscillating said member about said shaft includes an eccentric affixed to said shaft and embraced by said member with a rotative fit, and a pivot support for said member spaced from said shaft, and said adjusting means operates to adjust the position of said pivot support.

7. A compressor as described in claim 3, in which said adjusting means comprises a lever journalled for adjusting movement about said shaft.

8. A compressor as described in claim 3, in which said means for oscillating said member about said shaft includes an eccentric aflixed to said shaft and embraced by said member with a rotative fit, and said adjusting means comprises a lever journalled on said shaft for angular adjustment thereabout.

9. A compressor comprising a cylinder having inlet and outlet valves, a shaft, a piston reciprocable in the cylinder by the rotation of said shaft, an unloading valve at the closed end of said cylinder adapted to prevent compression in the cylinder, while the same is open, means for operating said unloading valve comprising a cam, an eccentric aflixed to said shaft for rotation therea e-"nets with, .a transverse member embracing said eccem tric with'a rotati-ve fit, a linkage between one end of said. transverse member and said cam for oscillating said cam, and a pivot supportior the other end of said transverse member, and means for adjusting the angular. position of said member with respect to the stroke phase of: said piston by varying the position of said pivot support to vary the phase relationship between said cam and: the stroke cycle.

10. A compressor comprising acylinder having inlet-and outlet valves; a shaft, a pistonreciprocable in the cylinder by rotation of. said shaft, means for selectively changing the effective volumetric displacement of said cylinder; comprising an unloading valve at the closed end of said cylinder adapted to prevent compression while said valve isopen, a cam, means-for'operatingsaid cam, means responsive to theoperation of said cam for controlling the operation offsaid in a valve-"to hold said valve open during a selected part of the compression stroke of saidpiston, a lever journalledfor adjusting movement about said shaft, and means responsive to the angular 5 movement of saidlever about said shaft forvarying the phase relationship between said cam and the stroke cycle ofsaid piston.

HARVEY W. BELL.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS 16 Number Name Date 966369 Petsche Aug. 9, 1910 1,0419'77 Nordberg Dec. 24, 1912 1,2654048 Carlsson May '7, 1918 1,706,373 Andersson Mar. 19, 1929 

